In electrocardiograph measurement systems, one approach seeks to determine the characteristics of the heart from the potential distribution over the body surface. This is accomplished by the use of multiple electrodes and compensating networks based on model studies with fixed locations of the respective electrodes relative to the heart.
In a typical system there may be five electrodes to be applied at specific locations relative to the heart, and a resistance network may be employed such that there are eight different network outputs from different pairs of which respective different electrocardiograph measurement signals are to be obtained in respective different measurement modes. In one such system, the modes are conventionally designated I, II, III, aVr, aVl, aVf, and V.